Bush-cutter for the manual mowing of grass and the like

ABSTRACT

A bush-cutter for the manual moving of grass and the like comprises a rod or a stiff arm, working as a handle, which supports at one end a cutting head rotating around on axis and having cutting means with a cutting element, for example a blade or a flexible rope or the like, and engine means which make the cutting head rotate through gearing means. According to the invention, the bush-cutter comprises spacing means ( 13 ), including a spacer ( 14 ) which swings coaxially to said cutting head ( 11 ) around said axis (X—X) and which, during the mowing of the grass, selectively contacts any possible obstacle at a radial distance from the cutting head ( 11 ), that is longer than the radial extension of the cutting element of said cutting means ( 11.2 ), in respect of the head, in order to avoid the contact of said cutting element with the obstacle.

The present invention relates to an improved bush-cutter for the mowingof grass and the like according to the first part of the main claim.

The well-known bush-cutter tools essentially include a rod or a stiffarm, working as a handle, that supports at one end a cutting headrotating around an axis and having cutting means with a cutting element,for example a blade or a flexible rope made of nylon or the like, and onthe other end engine means, for example a combustion engine, which makethe cutting head rotate through gearing mean.

In order to mow the grass, the operator grips the tool arm and movesforward, placing the cutting head near the ground and with its axis ofrotation substantially orthogonal in respect of the same, while throughmanual control means he adjusts the speed of rotation of the engine andconsequently the speed of rotation of the cutting head. The cuttingmeans, rotating together with the cutting head, mow the grass very closeto the ground.

However, often during the mowing the cutting means accidentally touchthe base of trees and shrubs trunks, causing the unwelcome barking, orother obstacles with the damages that this implies. This is partiallydue to the particular structure of the cutting means, which do not allowthe operator to perceive the right distance to be kept in order to avoidthe barking or even the cutting of the trunks, if they are small stockshrubs. EP-A-0.603.982 discloses a bush-cutter which comprises spacingmeans, including a spacer which swings around an axis parallel to theaxis around which the cutting head rotates.

According to U.S. Pat. No. 5,048,187 both axis of the spacer and thecutting head could be coincident.

In this bush-cutter the spacer is normally maintained in a workingposition in which, during the mowing of the grass, selectively contactsany possible obstacle at a radial distance from the cutting head, thatis longer than the radial extension of the cutting element of saidcutting means in respect of the head, avoiding the contact of saidcutting element with the obstacle.

However, when the bush-cutter is handled according to the normal forwarddirection of its cutting head, the spacer maintained in its workingposition could affect negatively the mowing of the grass.

It is therefore the principal object of the present invention to providean improved bush-cutter for the manual mowing of grass and the like,that allows to avoid the barking of trees and shrubs trunks and, anyhow,the contact of its cutting means with objects that have not to bedamaged during the mowing, without negatively affecting the moving ofthe grass when the bush-cutter is handled according to the normalforward direction of its cutting head.

Another object of this invention is to provide an improved bush-cutter,the construction of which can be simplified and which is safe andreliable and easy and comfortable to be used.

With these objects in view, the present invention provides a bush-cutterfor the mowing of grass and the like, whose essential characteristic isthe subject of the characterizing part of the main claim, which shouldbe regarded as incorporated here in its entirety.

Further advantageous features are described in the dependent claims.

The present invention will become clearer in the following detaileddescription, with reference to the attached drawings, which are providedpurely by way of non-restrictive example, in which:

FIG. 1 is a partial plan top view of the bush-cutter for the manualmowing of crass and the like according to an embodiment of th e presentinvention;

FIG. 2 is a side elevation view in direction of arrow II in FIG. 1.

In the drawings, the numeral 10 indicates a bush-cutter for the manualmowing of grass and the like, that incorporates the principles of thepresent invention and that is only partially illustrated (as it will bemore clear in the following part) for clarity reasons.

This bush-cutter 10 includes a cutting head 11 supported at one end of astiff handle arm 12 and rotating around an axis X—X (FIG. 2), whichduring the mowing is positioned substantially orthogonal in respect ofthe ground. (Head 11 and arm 12 are illustrated with dotted lines forclarity reasons).

The cutting head 11 has cutting means 11.2, which include a cuttingelement comprising a nylon flexible rope, which is substantiallyoutstretched—according to a diametrical direction—from opposite ends ofthe head (also said cutting means 11.2 are illustrated with dottedlines).

The cutting head 11 rotates, together with the cutting means 11.2,through engine means (well-known and therefore not illustrated) fastenedat the other end of the handle arm 12 (also not illustrated),

According to the present invention, in the bush-cutter 10 there areprovided spacing means 13 (FIG. 1) including a spacer 14, that swingscoaxially to the cutting head 11 around the said axis X—X and, duringthe mowing of the grass, contacts selectively any possible obstacle at aradial distance from the cutting head 11 that is longer than the radialextension of the cutting element of the cutting means 11.2, in order toavoid the contact of this cutting element with the obstacle.

The spacer 14 consists of a swinging blade 14.1, substantially like asector of a circle (plan view, FIG. 1). This swinging blade 14.1 ispivoted at the center on a pin 15 coaxially supported above the cuttinghead 11 through a bracket 16, which is arranged, in part, on said head11 and that extends, in part, along the handle arm 12.

Said bracket 16 is fastened, in a dismountable way, to the said arm 12through clamping means 17 with a securing screw 18.

The blade 14.1 is made of a light material, e.g. plastic material, woodor metallic alloy, and it has some lightening holes. Also the bracket,the clamping means and the securing screw can be made of the samematerials.

Spring means 19, for example a helical spring, working as return spring,are arranged between the bracket 16 and the swinging blade 14.1. Saidspring means 19 normally keep the blade 14.1 swung around the pin 15 ina rest position (as in FIG. 1), in which the blade—during the mowing ofthe grass—does not touch any possible obstacle before the cuttingelement of the cutting means 11,2, if the bush-cutter 10 is handledaccording to the normal forward direction of the cutting head 11 (asindicated with the arrow A in FIG. 1).

A fixed projection 20 juts out towards the top from the bracket 16 nearthe pin 15 and allows the blade 14.1 to stop, when it has beenautomatically swung in the rest position due to the action of the returnspring means 19.

Starting from the said rest position, the blade 14.1 can be swung aroundthe pin 15 (for example, counterclockwise, as indicated with the arrow Bin FIG. 1) according to a circumference arc of at least 180°, incontrast with the action of the said return spring means 19.

In said swinging blade 14.1 there is provided a clearance hole 14.2, theaxis of which is parallel to the axis X—X and which is arranged inproximity to the pin 15.

In the bracket 16, near the pin 15, there is provided a hole 16.1, theaxis of which is parallel to the axis X—X and which axially correspondsto the hole 14.2 of the blade 14.1 when said blade has been swung aroundthe pin 15 in the direction shown by the arrow B, starting from its restposition up to an intermediate working position, setting itsubstantially as an extension of the handle arm 12, that is making itrotate for a circumference arc substantially of 90°. In that workingposition, the blade 14.1 can be fixed in a discountable way to thebracket 16 and, therefore, to the handle arm 12, through the insertionof a set pin or a cotter pin (not illustrated) in the mentioned holes14.2/16.1, which are axially aligned each other.

Fixed in that working position, the blade 14.1 works as a fixed spacerin respect of the cutting head 11 and, when put against a linearobstacle, e.g. a wall or a hedge, it allows to mow the grass followingwith the bush-cutter 10 the shape of the obstacle, thus avoiding thatthe cutting means 11.2 touch the same.

When the pin is extracted from the holes 14.2/16.1, the blade 14.1 willbe automatically swung into its rest position due to the action of thereturn spring means 19.

As clearly illustrated in FIG. 1, the swinging blade 14.1 has a contactradial finger 21, that is removable and that projects outside one end ofits external curvilinear edge 14.3 (precisely, the front end of the edge14.3 in the rotation direction around the pin 15, according to the arrowB). Said contact finger 21 supports, on its free end, a roller 22 thatfreely rotates around an axis substantially parallel to the axis X—X.

By this arrangement, in order to mow the grass with the bush-cutter 10around an obstacle, the profile of which is curvilinear, for example atree trunk T (FIG. 1), after having fixed the finger 21, the swingingblade 14.1 (automatically swung into its rest position) is to be putagainst the obstacle T in two points, that is by means of the roller 22and a part of its curvilinear edge 14.3. Then, still keeping this twocontact points condition, the cutting head 11 is moved along arevolution arc around the obstacle (for example, counterclockwise asindicated from the arrow C in FIG. 1), through the handle arm 12. Duringsaid movement of the cutting head 11 the blade 14.1, working as swingingspacer, rotates around the pin 15 on a circumference arc even of 180°(according to the direction of the arrow B, starting, for example, fromits rest position), while it follows the obstacle profile, in order toallow the cutting means 11.2 to mow the surrounding grass without anycontact with the obstacle (for example, without any barking of the Ttrunk),

As regards the correct measuring of the cutting element of the cuttingmeans 11.2 in respect of the swinging blade 14.1 (so that the radialextension of said element from the cutting head 11 is as large aspossible while it has to be smaller than the radial distance keptbetween the head and the obstacle through the blade 14.1), in an area ofthe blade 14.1 near to its outer edge there is provided a locating andinspection clearance hole 14.4, the axis of which is substantiallyparallel to the axis X—X. During the setting up of the bush-cutter 10,through said hole 14.4 the operator looks at each end of the cuttingelement of the cutting means 11.2 and checks that it meets the axis ofthat hole. In the negative, he has to measure the radial extension ofsaid element in respect of the cutting head, placing the free end of theelement on the axis of the hole 14.4.

As will be clear from the foregoing, the spacer means 13 according tothe present embodiment of the invention consist of a fitting, that canbe assembled to a conventional bush-cutter through the attaching means16 and fastening means 17 and 18, which allow it to be adjusted in thelongitudinal direction of the handle arm 12, in order to assure thecorrect coaxiality between the swinging spacer 14 and the cutting head11.

In practice, of course, many variants may be made of what has beendescribed and illustrated purely by way of non-restrictive example,without thereby departing from the scope of the invention.

For example, the spacer means can be assembled into the structure of thebush-cutter according to the principles of the present invention.

What is claimed is:
 1. Bush-cutter for the manual mowing of grass, inwhich a rod or a stiff arm (12), working as a handle, supports at oneend a cutting head (11) rotating around an axis (X—X) and having acutting device with a cutting element, and in which an engine makes thecutting head rotate through gears, comprising a spacing device (13),including a spacer (14) which swings coaxially to said cutting head (11)around said axis (X—X) and which, during the mowing of the grass, may bebrought into contact with any possible obstacle determining a radialdistance of the obstacle from the cutting head (11), that is longer thanthe radial extension of the cutting element of said cutting device(11.2) in respect of the head, in order to avoid the contact of saidcutting element with the obstacle, characterized in that said spacingdevice (13) includes a spring (19), which normally maintains said spacer(14) in a rest position—swung around said axis (X—X)—, in which thespacer—during the mowing of the grass—does not touch any possibleobstacle before the cutting device (11.2), when the bush-cutter (10) ishandled according to the normal forward direction of its cutting head(11), and in which the cutting element consists of a flexible rope, saidbush-cutter further comprising a locating and inspection device (14.4)for the correct measuring of extending ends of the cutting element ofsaid cutting device (11.2) in respect of the spacer (14), andcharacterized in that said locating and inspection device (14.4)includes a clearance hole in proximity to the outer edge (14.3) of saidspacer (14) and distal from said axis (X—X), through which hole theoperator, during the setting up of the bush-cutter, looks at each end ofthe cutting element of said cutting device (11.2) and checks that itmeets the axis of that hole and, if not, he correctly sets the axis ofextension of the end of the said cutting element in respect of thecutting head, unwinding partially the cutting element.
 2. Bush-cutterfor the manual mowing of grass, in which a rod or a stiff arm (12),working as a handle, supports at one end a cutting head (11) rotatingaround an axis (X—X) and having a cutting device with a cutting element,and in which an engine makes the cutting head rotate through gears,comprising a spacing device (13), including a spacer (14) which swingscoaxially to said cutting head (11) around said axis (X—X) and which,during the mowing of the grass, may be brought into contact with anypossible obstacle determining a radial distance of the obstacle from thecutting head (11), that is longer than the radial extension of thecutting element of said cutting device (11.2) in respect of the head, inorder to avoid the contact of said cutting element with the obstacle,characterized in that said spacing device (13) includes a spring (19),which normally maintains said spacer (14) in a rest position—swungaround said axis (X—X)—, in which the spacer—during the mowing of thegrass—does not touch any possible obstacle before the cutting device(11.2), when the bush-cutter (10) is handled according to the normalforward direction of its cutting head (11), and in which said spacingdevice (13) includes an engagement or contact device (14.3, 21, 22) ofsaid spacer (14), through which the spacer contacts an obstacle, andkeeping the contact condition, while the cutting head (11) is movedsubstantially along a revolution arc around the obstacle—through thehandle arm (12)—, said spacer (14), working as a swinging spacer,rotates around the axis (X—X) for a circumference arc, following theobstacle profile, so that the cutting device (11.2) can mow surroundinggrass without touching the obstacle, and characterized in that saidspacing or contact device (14.3, 21, 22) of the spacer (14) includes afinger (21), which is connected in a dismountable way and that juts outin respect of the outer edge of the spacer.
 3. The bush-cutter of claim2, characterized in that said finger (21) has, on its free end, a roller(22), that freely rotates around an axis substantially parallel to saidaxis (X—X).
 4. Bush-cutter for the manual mowing of grass, in which arod or a stiff arm (12), working as a handle, supports at one end acutting head (11) rotating around an axis (X—X) and having a cuttingdevice with a cutting element, and in which an engine makes the cuttinghead rotate through gears, comprising a spacing device (13), including aspacer (14) which swings coaxially to said cutting head (11) around saidaxis (X—X) and which, during the mowing of the grass, may be broughtinto contact with any possible obstacle determining a radial distance ofthe obstacle from the cutting head (11), that is longer than the radialextension of the cutting element of said cutting device (11.2) inrespect of the head, in order to avoid the contact of said cuttingelement with the obstacle, characterized in that said spacing device(13) includes a spring (19), which normally maintains said spacer (14)in a rest position—swung around said axis (X—X)—, in which thespacer—during the mowing of the grass—does not touch any possibleobstacle before the cutting device (11.2), when the bush-cutter (10) ishandled according to the normal forward direction of its cutting head(11), in which the cutting element consists of a flexible rope wound inthe cutting head (11), wherein the cutting element has a first end and asecond end which extend from the cutting head (11) in oppositedirections, the radial extension of each end of said cutting elementbeing selectively set by an operator, and characterized in that thebush-cutter includes a locating and inspection device (14.4) for thecorrect measuring of the extending ends of the cutting element of saidcutting device (11.2) in respect of the spacer (14), and which allow theoperator to check that the radial extension of each end of said cuttingelement from the cutting head (11) is as large as possible, but smallerthan the radial distance that the spacer (14) keeps between said headand an obstacle, and to correctly set the radial extension of each endof said cutting element, when necessary.
 5. The bush-cutter of claim 4,characterized in that said locating and inspection device (14.4)includes a clearance hole in proximity to the outer edge (14.3) of saidspacer (14) and distal from said axis (X—X), through which hole theoperator, during the setting up of the bush-cutter, looks at each end ofthe cutting element of said cutting device (11.2) and checks that itmeets the axis of that hole and, if not, he correctly sets the axis ofextension of the end of the said cutting element in respect of thecutting head, unwinding partially the cutting element.
 6. Bush-cutterfor the manual mowing of grass, in which a rod or a stiff arm (12),working as a handle, supports at one end a cutting head (11) rotatingaround an axis (X—X) and having a cutting device with a cutting element,and in which an engine makes the cutting head rotate through gears,comprising a spacing device (13), including a spacer (14) which swingscoaxially to said cutting head (11) around said axis (X—X) and which,during the mowing of the grass, may be brought into contact with anypossible obstacle determining a radial distance of the obstacle from thecutting head (11), that is longer than the radial extension of thecutting element of said cutting device (11.2) in respect of the head, inorder to avoid the contact of said cutting element with the obstacle,characterized in that said spacing device (13) includes a spring (19),which normally maintains said spacer (14) in a rest position—swungaround said axis (X—X)—, in which the spacer—during the mowing of thegrass—does not touch any possible obstacle before the cutting device(11.2), when the bush-cutter (10) is handled according to the normalforward direction of its cutting head (11), and characterized in thatsaid spacer (14) consists of a swinging blade (14.1).
 7. The bush-cutterof claim 6, in which said spacing device (13) is embodied in a fittingthat is assembled in a dismountable way, characterized in that saidspacing device (13) includes a spacer (14), pivoted on a pin (15)supported coaxial above the cutting head (11) through a bracket (16),which is partially arranged on the cutting head (11) and partiallyextends along the handle arm (12); said bracket (16) is fastened in adismountable way to the arm (12).
 8. The bush-cutter of claim 3, whereinthe bracket (16) is fastened to the arm (12) through a clamp (17) with asecuring screw (18).